The use of radiation to treat medical conditions comprises a known area of prior art endeavor. For example, radiation therapy comprises an important component of many treatment plans for reducing or eliminating unwanted tumors. Unfortunately, applied radiation does not inherently discriminate between unwanted areas and adjacent healthy tissues, organs, or the like that are desired or even critical to continued survival of the patient. As a result, radiation is ordinarily applied in a carefully administered manner to at least attempt to restrict the radiation to a given target volume.
Treatment plans typically serve to specify any number of operating parameters as pertain to the administration of such treatment with respect to a given patient using a specific radiation therapy treatment platform. Such treatment plans are often optimized prior to use. (As used herein, “optimization” will be understood to refer to improving upon a candidate treatment plan without necessarily ensuring that the optimized result is, in fact, the singular best solution.) Many optimization approaches use an automated incremental methodology where various optimization results are calculated and tested in turn using a variety of automatically-modified (i.e., “incremented”) treatment plan optimization parameters.
Treatment plans are typically generated as a function of user-specified dosimetric goals. In many cases dose optimization proceeds as a function of both a presently-planned dose (i.e., the dose being optimized for a particular radiation treatment session) and a so-called base dose. The base dose is an aggregated per-patient metric representing the radiation dosage received in earlier radiation treatment sessions (if any), during the same day (i.e., “fraction”) (if any) as the session currently being optimized, and future sessions as well (if any).
These references to previous and future dosings for a particular patient generally refer to dosings that are administered as part of an overall unified and integrated effort to treat a particular unwanted biological condition such as a tumor or group of tumors. Accordingly, and usually, it is not contemplated that the base dose will include radiation dosings that might have nothing to do with the present course of treatment such as, for example, dentistry x-rays. That said, however, in some cases it may be appropriate to include ancillary exposures of radiation (such as a series of x-rays to view and diagnosis a broken bone or a CT scan to diagnose some other unrelated condition) when computing the base dose.
A typical prior art practice is to manually calculate the base dose by combining dose distributions from their corresponding different events. Such an approach, of course, is prone to human error, oversight, misinterpretations, and misunderstandings, all of which can lead to an inaccurate base dose. An incorrect base dose, in turn, can lead to a sub-optimum radiation treatment plan.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present teachings. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present teachings. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.